Well, I've been playing Spelunky pretty extensively for the last week or so, and a couple of days ago, I finally had a breakthrough: I had been totally getting my ass handed to me in the Jungle area constantly, but after playing only that zone over and over again for a couple of hours, I reached the point where I could own it pretty consistently. The mines, frozen caves and temple have never given me any problems, so once I reached the point where I could reliably pass through the jungle, I was at a place where I could reach Olmec seven or eight times out of ten. I have yet to actually beat him, but hell, I can give him a pretty good run. I've been watching videos of other people playing, and, though I thought I was mediocre (at best) at the game, it actually looks like I'm pretty decent at it, at least compared to them.
I still want to beat Olmec, though. I had a surefire Hell run going earlier, but ran out of bombs while fighting Olmec, and made a silly mistake while trying to get him to break through the last row of bricks by himself and ended up crushed. I'll get him yet, though.